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Method and a circuit arrangement for signal processing in a telecommunication system

  • US 6,061,385 A
  • Filed: 03/10/1997
  • Issued: 05/09/2000
  • Est. Priority Date: 03/12/1996
  • Status: Expired due to Fees
First Claim
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1. A method for processing a received spread spectrum signal and a received frequency modulated signal, in which:

  • a radio frequency signal is received (1,

         2), the received radio frequency signal being either a spread spectrum signal or a frequency modulated signal,the received signal is converted into an intermediate frequency signal (3, 1. IF),an intermediate frequency signal processing is performed (4a, 4b) to provide processed intermediate frequency signals, comprising the following steps, namely;

    a frequency modulated intermediate frequency signal is formed by use of a first band-pass filter (4a), and spread spectrum intermediate frequency signal is formed by use of a second band-pass filter (4b),with respect to the derived signals, either a signal derived from the received spread spectrum signal or the signal derived from the received frequency modulated signal, respectively, is selected by switching means (5), andthe signal selected by said switching means, or a signal derived from it, is converted into a second intermediate frequency signal (2. IF) by use of converting means (6,

         7),a speech signal is added to said first intermediate signal or to said second intermediate signal in order to form a sum signal by use of adding means (40),a sampled signal from said sum signal is formed by use of sampling means (41),the sampled intermediate frequency signals are converted into baseband signals, comprising the following steps, namely the spread spectrum signal or the frequency modulated signal is converted into a baseband signal by use of converting means (32, 42a, 42b), the spread spectrum signal is digitally filtered by filtering means (43a, 43b), the spread spectrum of the filtered spread spectrum signal is despread by use of despreading means (118a, 118b,

         119), the frequency modulated signal is digitally demodulated by use of demodulating means (33), and the sampled signal is filtered by use of filter means (44) in order to separate the speech signal from the intermediate frequency signal.

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